If Mac-T insists on a a bold move to bring a new player in, I think the first thing he should do is bring in a #1 defenseman.

That being said, it's a tough move to make, but the following legitimate top-4 defensemen would suffice IMO:

Toni Lydman - underrated LHD who has been solid for 10+ years now. Great compliment to young developing offensive defensemen, and could be ideal partner for Justin Schultz.Proposed move: Sign to 3yr, $3.25M deal

Johnny Boychuk - going to be tough to get out of Boston, but he's looked good paired with a true #1 defenseman in Chara, and not out of place with Ference on #2 pairing. RHD with a big shot, physical play, and good defense. No real place for our roster though unless one of Petry/Schultz is moved.Proposed move: Hemsky+ for Boychuk

Niklas Hjalmarsson - He's playing the toughest minutes amongst Chicago defenseman alongside Oduya and the pair has kept its head out of the water. He's emerging into his own, and would be a perfect partner for Justin Schultz as he develops.Proposed move: Hjalmarsson for Gagner

Brian Campbell - he's had a rough year, but numbers don't tell the whole story for him this season. Florida is a terrible team with terrible goaltending, and all of their defensemen have struggled because of this. He's faced the toughest competition on the team and his -20 is still better than 2 other defensemen on his team. A risk, but could be had for a Hemsky-like player. Puck-moving LHD.Proposed trade: Hemsky for Campbell; Horcoff for Campbell if Tallon is looking for a cheap(er) buy-out

Good list and I left the 4 that seem the most realistic.

If the Oil could do something around Hemksy+ N Schultz for Campbell, then possibly add Orpik in a deal for picks as has been previously discussed, we would look good going into next year.